Conventionally, as a display device usable for a display of a mobile terminal, a TV or the like, an organic EL (electroluminescence) display device including an organic EL element is known. An organic EL display device has advantages of emitting bright light, having superb viewing angle characteristics, and the like, and thus rapid development thereof is desired to provide a display device replacing a liquid crystal display device.
Usually, an organic EL display device includes a plurality of pixels each including a light emitting element (specifically, organic EL element). The pixels each include a pixel electrode, and the pixel electrode is used to form a light emitting element. In general, an insulating film referred to as a bank (or a rib) is located on the pixel electrodes. The bank has a plurality of openings respectively corresponding to the plurality of pixel electrodes, and a part of a top surface of each pixel electrode is exposed in the corresponding opening. The organic EL display device having such a structure is disclosed in, for example, Japanese Laid-Open Patent Publication No. 2002-324662.